Put the spinach in a saucepan with a little water (preferably so that the bottom of the saucepan is covered with water).
Peel the potatoes, cut into pieces and simmer for 20 minutes. If you prefer, you can leave it whole and cut it later. Then let the eggs simmer for 10 minutes.
Melt the butter or margarine, then add the flour and stir with the whisk and gradually add the milk. Meanwhile, keep stirring until the sauce is nice and creamy. If you want, you can stir in some cream. Then dissolve the stock cube in the sauce. Simmer for a few minutes and season with the spices.
Peel the eggs and add them to the sauce. Season the spinach to taste, put a little butter on the potatoes if necessary and serve everything together.
Since you make the egg sauce more by feeling, the quantities given may vary slightly.